<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>


    <script>


        var i = 1;

        // typeof: 类型检测
        // typeof i -> Number, i是Number类型
        console.log(typeof i)
        console.log(i instanceof Number)


        var num = new  Number(10)
        console.log(num instanceof Number)
        console.log(typeof num)



        // for (var j = 0; j < 100; j++) {
        //    //  alert("弹出框")
        //     console.log("输出到控制台" + j)
        // }


    </script>

</body>
</html>
